April 23, 2025
On Monday, April 21st, Kate McLarney-Popham successfully defended her MSc thesis, titled "Computational Modeling of the Heat Treatment of White Oak Bound for Spirit Maturation".
Congrats!
April 23, 2025
On Thursday, April 17th, Kirsten Ford successfully defended her MSc thesis, titled "Kentucky Re-entry Universal Payload System (KRUPS): Second Atmospheric Re-entry Flight".
Congrats!
April 11, 2025
January 13, 2025
November 11, 2024
October 7, 2024
The talks were given in the 2024 Southeast Regional Space Grant meeting at Oxford, MS, September 26-27, 2024.
September 20, 2024
Krups has been featured during the Engineering Takes Flight event.
August 13, 2024
August 13, 2024
January 17, 2024
December 11, 2023
December 11, 2023
December 11, 2023
December 11, 2023
December 11, 2023
July 27, 2022
July 27, 2022
July 27, 2022
May 12, 2022
May 6, 2022
March 14, 2022
March 2, 2022
From left to right: Raghava Davuluri, Page Askins, Bibin Joseph, Simon Schmidt, Jino George, Alex Zibitsker, Rick Fu, Ares Barrio, Berk Gur, Sujit Sinha, Kirsten Ford, Kristen Price, John Schmidt, Matt Ruffner, Alexandre Martin
Missing from the picture: Craig Meade, Luke Fortner, Sean McDaniel, Justin Cooper, Kate Rhoads, Tori DuPlessis, Kate MacLarney, Mohammad Khaleel
January 11, 2022
Highlights
• Particle tracking velocimetry conducted on particles shedding from ablative thermal protection system materials.
• Tests indicate spallation unaffected by pyrolysis gas formation, but impact of environment largely felt through effects due to gas composition.
• Effect of sample geometry suggested that surface shear stress plays a role in spallation particle shedding into the flow.
• An approach was devised to estimate particle diameter based on the acceleration of the particles once they left the material sample.
• Particle diameters were in the range expected for formation from both individual fibers as well as larger groups of fibers.
Price, K. J., Borchetta, C. G., Hardy, J. M., Panerai, F., Bailey, S. C. C., and Martin, A., “Arc-Jet Measurements of Low-Density Ablator Spallation,” Experimental Thermal and Fluid Science, Vol. 133, No. 110544, May 2022.
doi: 10.1016/j.expthermflusci.2021.11054
January 11, 2022
[1] Banerjee, A., Martin, A., and Poovathingal, S., “Estimating Effective Radiative Properties and In-Depth Radiative Heating of Porous Ablators,” AIAA SciTech Forum, AIAA Paper 2022-1640, Jan 2022. DOI:10.2514/6.2022-1640
[2] Cooper, J. M., Salazar, G., and Martin, A., “Numerical Investigation of Film Coefficient Engineering Methodology for Dissociated, Chemically Reacting Boundary Layers,” AIAA SciTech Forum, AIAA Paper 2022-1907, Jan 2022. DOI:10.2514/6.2022-1907
[3] Davuluri, R. S. C., Fu, R., Tagavi, K. A., and Martin, A., “Numerical investigation on the effect of spectral radiative heat transfer within an ablative material,” AIAA SciTech Forum, AIAA Paper 6.2022-1283, Jan 2022. DOI:10.2514/6.2022-1283
[4] Fortner, L., Maddox, J., and Martin, A., “Numerical investigation of an oxyacetylene torch with regards to an ablative material used in re-entry,” AIAA SciTech Forum, AIAA Paper 2022-1498, Jan 2022. DOI:10.2514/6.2022-1498
[5] Fu, R., Schmitt, S., and Martin, A., “Thermo-Chemical-Structural Modeling of Carbon Fiber Pitting and Failure Mechanism,” AIAA SciTech Forum, AIAA Paper 2022-1282, Jan 2022. DOI:10.2514/6.2022-1282
[6] Schmidt, J. D., Nichols, J. T., Ruffner, M., Nolin, R., Smith, W. T., and Martin, A., “Kentucky Re- Entry Universal Payload System (KRUPS): Design and Testing for Hypersonic Re-Entry Flight,” AIAA SciTech Forum, AIAA Paper 2022-1576, Jan 2022. DOI:10.2514/6.2022-1576
[7] Schmitt, S., Fu, R., and Martin, A., “Extension of Kinetic Monte Carlo Simulation Framework to Multilayer Graphene and Graphite Oxidation,” AIAA SciTech Forum, AIAA Paper 2022-1284, Jan 2022. DOI:10.2514/6.2022-1284
[8] Schmitt, S. and Martin, A., “Kinetic Monte Carlo Simulations of Nitrogen-Carbon Gas-Surface Reaction at High Temperatures,” AIAA SciTech Forum, AIAA Paper 10.2514/6.2022-0113, Jan 2022. DOI:10.2514/6.2022-0113
[9] Seif, M., Puppo, J., Zlatinov, M., Schaffarzick, D., Martin, A., and Beck, M., “Stochastic mechanical modeling of Duocel foam from micro- to macro- length scales,” AIAA SciTech Forum, AIAA Paper 2022-0627, Jan 2022. DOI:10.2514/6.2022-0627
[10] Zibitsker, A., McQuaid, J., Brehm, C., and Martin, A., “Development and Verification of a Mesh Deformation Scheme for a Three Dimensional Ablative Material Solver,” AIAA SciTech Forum, AIAA Paper 2022-1285, Jan 2022. DOI:10.2514/6.2022-1285
[11] Zibitsker, A., McQuaid, J., Martin, A., and Brehm, C., “Fully-Coupled Simulation of Low Temperature Ablator and Hypersonic Flow Solver.” AIAA SciTech Forum, AIAA Paper 2022-0676, Jan 2022. DOI:10.2514/6.2022-0676
September 21, 2021
The P1 approximation to the radiative transfer equation is coupled to a material response code in order to model ablative materials. These types of materials are used as thermal protection systems for atmospheric entry vehicles. Several test cases are presented to verify the implementation and to validate the approach. Representative conditions -- mimicking an arc-jet, a radiant heating facility, and an atmospheric entry trajectory -- are used to demonstrate the validity of the coupled model. The code is then used to replicate an experiment that studies the effects of the wavelength on the thermal response of charring ablators. Two lasers are used to deliver the heat pulse. The first laser, at a wavelength of 1.07 micron, deposits the energy within the material, as opposed to the 10.6 micron laser, which mostly does it on the surface. The numerical results verify the findings of the experiment, thus confirming the importance of spectrally resolving the radiative heat flux within charring ablators.
Martin, A. and Panesi, M., “Radiative transmission and absorption within the thermal protection system of an atmospheric entry spacecraft,” Journal of Spacecraft and Rockets, 2020.
doi:10.2514/1.A35029
April 30, 2021
Davuluri, R. S. C., Bailey, S. C. C., Tagavi, K. A., and Martin, A., “A drag coefficient model for lagrangian particle dynamics relevant to high-speed flows,” International Journal of Heat and Fluid Flow, vol. 87, 2021, Article 108706.
doi: 10.1016/j.ijheatfluidflow.2020.108706.
Omidy, A. D., Cooper, J. M., Tagavi, K. A., and Martin, A., “VISTA, an open Avcoat material database for material response modeling,” JANNAF Journal of Propulsion and Energetics, vol. 12, no. 1, 2021.
Ho, M., Leclaire, S., Trépanier, J.-Y., Reggio, M., and Martin, A., “Permeability cal- culation of a fibrous thermal insulator using the lattice boltzmann method,” Journal of Thermophysics and Heat Transfer, 2021.
doi: 10.2514/1.T6154.
Cochell, T. J., Unocic, R. R., Grana-Otero, J., and Martin, A., “Nanoscale oxidation behavior of carbon fibers revealed with in situ gas cell stem,” Scripta Materialia, vol. 199, 2020, Article 113820.
doi: 10.1016/j.scriptamat.2021.113820.
Duzel, U., Schroeder, O. M., Zhang, H., and Martin, A., “Numerical simulation of an arc jet test section,” Journal of Thermophysics and Heat Transfer, vol. 34, no. 2, pp. 393–403, 2020.
doi: 10.2514/1.T5722.
Fu, R., Weng, H., Wenk, J. F., and Martin, A., “Thermal expansion for charring ablative materials,” Journal of Thermophysics and Heat Transfer, vol. 34, no. 1, pp. 57– 65, 2020.
doi: 10.2514/1.T5718.
Weng, H., Duzel, U., Fu, R., and Martin, A., “Geometric effects on charring ablator: modeling of the full-scale stardust heat shield,” Journal of Spacecraft and Rockets, vol. 58, no. 2, pp. 302–315, 2020.
doi: 10.2514/1.A34828.
Panerai, F., Cochell, T. J., Martin, A., and White, J. D., “Experimental measurements of the high-temperature oxidation of carbon fibers,” International Journal of Heat and Mass Transfer, vol. 136, pp. 972–986, 2019.
doi: 10.1016/j.ijheatmasstransfer.2019.03.018.
Rostkowski, P., Venturi, S., Omidy, A. D., Weng, H., Martin, A., and Panesi, M., “Calibration and uncertainty quantification of vista ablator material database using bayesian inference,” Journal of Thermophysics and Heat Transfer, vol. 33, no. 2, pp. 356– 369, 2019.
doi: 10.2514/1.T5396.
Zhang, H., Martin, A., and Wang, G., “Numerical analysis of time accuracy of a primitive variable-based formulation of the conservative form of the governing equations for compressible flows,” International Journal of Computational Fluid Dynamics, vol. 33, no. 1-2, pp. 1–9, 2019.
doi: 10.1080/10618562.2018.1549730.
Bailey, S. C. C., Bauer, D., Panerai, F., Splinter, S. C., Danehy, P. M., Hardy, J. M., and Martin, A., “Experimental analysis of spallation particle trajectories in an arc-jet environment,” Experimental Thermal and Fluid Science, vol. 93, pp. 319–325, 2018.
doi: 10.1016/j.expthermflusci.2018.01.005
April 30, 2021
Kristen Price, a PhD student in GSIL, Selected as a NASA Space Technology Graduate Researcher:
https://www.engr.uky.edu/news/2021/04/kristen-price-selected-nasa-space-...
April 30, 2021
April 30, 2021
MSc student in GSIL, Luke Fortner, was selected for various awards:
https://www.engr.uky.edu/news/2020/12/luke-fortner-named-wuerffel-trophy...
https://www.engr.uky.edu/news/2020/09/luke-fortner-named-2020-allstate-a...
https://www.engr.uky.edu/news/2020/08/luke-fortner-nominated-2020-willia...
April 30, 2021
The work of Justin Cooper, a PhD student in GSIL, featured in NASA News:
https://www.nasa.gov/centers/armstrong/features/armstrong-assists-with-o...
December 27, 2018
November 9, 2018
July 17, 2018
[1] Sparks, J. D., Myers, G. I., Whitmer, E. C., Nichols, J. T., Dietz, C. J., Khouri, N., Smith, S. W., and Martin, A., “Overview of the second test-flight of the Kentucky Re-entry Universal Payload System (KRUPS),” 12th AIAA/ASME Joint Thermophysics and Heat Transfer Conference, AIAA Paper 2018- 3589, Atlanta, GA, June 2018.
DOI: 10.2514/6.2018- 3589
[2] Cooper, J. M., Schroeder, O. M., Weng, H., and Martin, A., “Implementation and Verification of a Surface Recession Module in a Finite Volume Ablation Solver,” 12th AIAA/ASME Joint Thermophysics and Heat Transfer Conference, AIAA Paper 2018-3272, Atlanta, GA, June 2018.
DOI: 10.2514/6.2018- 3272
February 8, 2018
A new journal article was recently published in the journal of Experiments Fluids:
Abstract
The near surface flow over a dimpled surface with flow injection through it was documented using time-resolved particle image velocimetry. The instantaneous flow structure, time-averaged statistics, and results from snapshot proper orthogonal decomposition were used to examine the coherent structures forming near the dimpled surface. In particular, the modifications made to the flow structures by the addition of flow injection through the surface were studied. It was observed that without flow injection, inclined flow structures with alternating vorticity from neighboring dimples are generated by the dimples and advect downstream. This behavior is coupled with fluid becoming entrained inside the dimples, recirculating and ejecting away from the surface. When flow injection was introduced through the surface, the flow structures became more disorganized, but some of the features of the semi-periodic structures observed without flow injection were preserved. The structures with flow injection appear in multiple wall-normal layers, formed from vortical structures shed from upstream dimples, with a corresponding increase in the size of the advecting structures. As a result of the more complex flow field observed with flow injection, there was an increase in turbulent kinetic energy and Reynolds shear stress, with the Reynolds shear stress representing an increase in vertical transport of momentum by sweeping and ejecting motions that were not present without flow injection.
Borchetta, C. G., Martin, A., and Bailey, S. C. C., “Examination of the effect of blowing on the near-surface flow structure over a dimpled surface,” Experiments in Fluids, vol. 59, no. 3, Article 36, 2017.
doi: 10.1007/s00348-018-2498-z.
January 26, 2018
A new journal article was recently published in the journal of Experimental Thermal and Fluid Science:
Abstract
Spallation is a phenomenon in which solid particles are ejected off the surface of an ablative material in a high-enthalpy, high-shear flow field. The main contributor to this phenomenon in carbon-based heat shields is the mechanical erosion of carbon fibers weakened by oxidation decomposition. The dynamics of this phenomenon, which are poorly characterized in the literature, strongly affect the ablation rate of the material. In state-of-the-art codes, ablation by spallation is modeled using a “failure” ablation rate that is empirically determined. The present study aims at understanding the rate of ablation of low-density carbon materials. Results from a test campaign at the NASA Langley Hypersonic Materials Environmental Test System (HYMETS) arc jet facility are used to examine spallation. High-speed multi-camera imagery at 44,000 fps is used to generate velocity vectors of spalled particles emitted from carbon-fiber samples exposed to an arc jet airflow. The imagery recorded approximately 4×106 unique particles, indicating that spallation is a potentially non-trivial process. The velocities of the particles ejected from the surface were found to be between 10 m/s and 20 m/s, accelerating to velocities as high as 250 m/s further away from the sample surface. Although the particle diameters were not directly observable, estimates suggest anywhere from 0.06% to 5.6% of the mass loss from the sample occurred due to spallation.
Bailey, S. C. C., Bauer, D., Panerai, F., Splinter, S. C., Danehy, P. M., Hardy, J. M., and Martin, A., “Experimental analysis of spallation particle trajectories in an arc-jet environment,” Experimental Thermal and Fluid Science, 2018.
doi: 10.1016/j.expthermflusci.2018.01.005
January 26, 2018
Two new articles were recently presented at the AIAA Aerospace Science Meeting (SciTech 2018):
Sparks, J. D., Whitmer, E. C., Myers, G. I., Montague, C. C., Dietz, C. J., Khouri, N., Nichols, J. T., Smith, S. W., and Martin, A., “Overview of the first test-flight of the Kentucky re-entry universal payload system (KRUPS),” 56th AIAA Aerospace Sciences Meeting, AIAA Paper 2018-1720, Kissimmee, FL, January 2018.
doi: 10.2514/6.2018-1720
Duzel, U., Schroeder, O. M., and Martin, A., “Computational prediction of nasa langley hymets arc jet flow with KATS,” 56th AIAA Aerospace Sciences Meeting, AIAA 2018-1719, Kissimmee, FL, January 2018.
doi: 10.2514/6.2018-1719
December 13, 2017
Louisville main newspaper, the Courier-Journal, recently published an article about the research of the Gas-Surface Interaction Lab: https://www.courier-journal.com/story/tech/science/2017/09/14/kentucky-scientists-help-nasa-prepare-deep-space-missions/525000001/
December 13, 2017
A new journal article was recently published in the Journal of Computational Physics:
This paper presents a data-driven computational model for simulating unsteady turbulent flows, where sparse measurement data is available. The model uses the retrospective cost adaptation (RCA) algorithm to automatically adjust the closure coefficients of the Reynolds-averaged Navier-Stokes (RANS) k - ω turbulence equations to improve agreement between the simulated flow and the measurements. The RCA-RANS k - ωmodel is verified for steady flow using a pipe-flow test case and for unsteady flow using a surface-mounted-cube test case. Measurements used for adaptation of the verification cases are obtained from baseline simulations with known closure coefficients. These verification test cases demonstrate that the RCA-RANS k - ω model can successfully adapt the closure coefficients to improve agreement between the simulated flow field and a set of sparse flow-field measurements. Furthermore, the RCA-RANS k - ω model improves agreement between the simulated flow and the baseline flow at locations at which measurements do not exist. The RCA-RANS k - ω model is also validated with experimental data from 2 test cases: steady pipe flow, and unsteady flow past a square cylinder. In both test cases, the adaptation improves agreement with experimental data in comparison to the results from a non-adaptive RANS k - ω model that uses the standard values of the k - ω closure coefficients. For the steady pipe flow, adaptation is driven by mean stream-wise velocity measurements at 24 locations along the pipe radius. The RCA-RANS k - ω model reduces the average velocity error at these locations by over 35%. For the unsteady flow over a square cylinder, adaptation is driven by time-varying surface pressure measurements at 2 locations on the square cylinder. The RCA-RANS k - ω model reduces the average surface-pressure error at these locations by 88.8%.
[1] Li, Z., Bailey, S. C. C., Hoagg, J. B., and Martin, A., “A retrospective cost adaptive Reynolds-averaged Navier-Stokes k-w model for data-driven unsteady turbulent simulation,” Journal of Computational Physics, 2018.
DOI:10.1016/j.jcp.2017.11.037
November 2, 2017
A new journal article was recently published in the AIAA Journal of Thermophysics and Heat Transfer:
Thermomechanical analysis of ablative materials is of great importance to the design of thermal-protection systems. A finite volume method for coupling the mechanical and thermal response models for ablation problems is proposed. This method is capable of simulating both transient and static thermomechanical responses. The solver is verified against analytic solutions and through code-to-code comparisons. It is then fully coupled to a state-of-the-art material response code. Coupled results show that high temperature gradients have significant effects on the mechanical performance and stress generation. The magnitude and the location of the stress concentration can play a significant role in structural integrity, and may lead to crack formation as well as spallation.
[1] Fu, R., Weng, H., Wenk, J. F., and Martin, A., “Thermo-mechanical coupling for charring ablators,” Journal of Thermophysics and Heat Transfer, 2017. doi: 10.2514/1.T5194.
August 28, 2017
Story on the KRUPS project:
https://uknow.uky.edu/research/after-developing-small-spacecraft-uk-students-help-launch-it-nasa-wallops
August 5, 2017
A new paper is available:
Martin, A., Zhang, H., and Tagavi, K. A., “An introduction to a systematic derivation of surface balance equations without the excruciating pain,” International Journal of Heat and Mass Transfer, Vol. 115, Part A, December 2017, pp. 992–999.
DOI: 10.1016/j.ijheatmasstransfer.2017.07.078
Analyzing complex fluid flow problems that involve multiple coupled domains, each with their respective set of governing equations, is not a trivial undertaking. Even more complicated is the elaborate and tedious task of specifying the interface and boundary conditions between various domains. This paper provides an elegant, straightforward and universal method that considers the nature of those shared boundaries and derives the appropriate conditions at the interface, irrespective of the governing equations being solved. As a first example, a well-known interface condition is derived using this method. For a second example, the set of boundary conditions necessary to solve a baseline aerothermodynamics coupled plain/porous flow problem is derived. Finally, the method is applied to two more flow configurations, one consisting of an impermeable adiabatic wall and the other an ablating surface.
June 14, 2017
Four new GSIL conferences papers, presented at the AIAA AVIATION 2017 meeting:
[1] Irvan, M. L., Barrow, C., Keen, A., Maddox, J. F., and Martin, A., “Physics Based Modeling of Fibrous High Porosity Insulation Materials Using Comparative Cut-Bar Experimentation,” 24th AIAA Aerodynamic Decelerator Systems Technology Conference, AIAA Paper 2017-3887, Denver, CO, June 2017.
doi: 10.2514/6.2017-3887
[2] Weng, H. and Martin, A., “Development of a Universal Solver and Its Application to Ablation Problems,” 47th AIAA Thermophysics Conference, AIAA Paper 2017-3355, Denver, CO, June 2017.
doi: 10.2514/6.2017-3355
[3] Omidy, A. D., Weng, H., Martin, A., and Gran ̃a-Otero, J. C., “Modeling Gasification of Carbon Fiber Preform in Oxygen-Rich Environments,” 47th AIAA Thermophysics Conference, AIAA Paper 2017-3686, Denver, CO, June 2017.
doi: 10.2514/6.2017-3686
[4] Omidy, A. D., Cooper, J. M., Fu, R., Weng, H., and Martin, A., “Development Of An Open-Source Avcoat Material Database, VISTA,” 47th AIAA Thermophysics Conference, AIAA Paper 2017-3356, Denver, CO, June 2017.
doi: 10.2514/6.2017-3356
May 27, 2017
New journal article in the Journal of Computational Physics:
This paper presents a new data-driven adaptive computational model for simulating turbulent flow, where partial-but-incomplete measurement data is available. The model automatically adjusts the closure coefficients of the Reynolds-averaged Navier–Stokes (RANS) k–ω turbulence equations to improve agreement between the simulated flow and the measurements. This data-driven adaptive RANS k–ω (D-DARK) model is validated with 3 canonical flow geometries: pipe flow, backward-facing step, and flow around an airfoil. For all test cases, the D-DARK model improves agreement with experimental data in comparison to the results from a non-adaptive RANS k–ω model that uses standard values of the closure coefficients. For the pipe flow, adaptation is driven by mean stream-wise velocity data from 42 measurement locations along the pipe radius, and the D-DARK model reduces the average error from 5.2% to 1.1%. For the 2-dimensional backward-facing step, adaptation is driven by mean stream-wise velocity data from 100 measurement locations at 4 cross-sections of the flow. In this case, D-DARK reduces the average error from 40% to 12%. For the NACA 0012 airfoil, adaptation is driven by surface-pressure data at 25 measurement locations. The D-DARK model reduces the average error in surface-pressure coefficients from 45% to 12%.
Li, Z., Zhang, H., Bailey, S. C., Hoagg, J. B., and Martin, A., “A Data-Driven RANS k-ω approach for modeling turbulent flows,” Journal of Computational Physics, vol. 345, 2017, pp. 111–131.
doi:10.1016/j.jcp.2017.05.009
May 17, 2017
A new journal article was recently published in the International Journal of Heat and Mass Transfer:
Material properties and oxidation behavior of low-density felts used as substrates for conformal carbon/ phenolic ablators were compared with those of a rigid carbon fiber preform used to manufacture heritage lightweight ablators. Synchrotron X-ray micro-tomography measurements were performed to character- ize the materials’ microstructure at the scale of the fibers. Using the tomography voxels as computational grids, tortuosity in the continuum regime, and room temperature conductivity were computed. Micro- scale simulations of the oxidation of carbon fibers were carried out using a random walk model for oxy- gen diffusion and a sticking probability law to model surface reactions. The study shows that, due to a higher porosity and lower connectivity, the felt materials have lower thermal conductivity but a faster recession rate than that of the rigid preform. Challenges associated with computations based on micro-tomography are also discussed.
[1] Panerai, F., Ferguson, J. C., Lachaud, J. R., Martin, A., Gasch, M. J., and Mansour, N. N., “Analysis of rigid and flexible substrates for lightweight ablators based on X-ray micro-tomography,” International Journal of Heat and Mass Transfer, Vol. 108, Part A, May 2017, pp. 801–811.
DOI: 10.1016/j.ijheatmasstransfer.2016.12.048
March 15, 2017
New article in Aerospace Science and Technology!
Accurate thermodynamic properties for species found in carbon-phenolic gas mixtures are essential in predicting material response and heating of carbon-phenolic heat shields of planetary entry vehicles. A review of available thermodynamic data for species found in mixtures of carbon-phenolic pyrolysis and ablation gases and atmospheres rich with C, H, O, and N such as those of Earth, Mars, Titan, and Venus, is performed. Over 1200 unique chemical species are identified from four widely used thermodynamic databases and a systematic procedure is described for combining these data into a comprehensive model. The detailed dataset is then compared with the Chemical Equilibrium with Applications thermodynamic database developed by NASA in order to quantify the differences in equilibrium thermodynamic properties obtained with the two databases. In addition, a consistent reduction methodology using the mixture thermodynamic properties as an objective function is developed to generate reduced species sets for a variety of temperature, pressure, and elemental composition spaces. It is found that 32 and 23 species are required to model carbon-phenolic pyrolysis gases mixed with air and CO2, respectively, to maintain a maximum error in thermodynamic quantities below 10%.
[1] Scoggins, J. B., Rabinovich, J., Barros-Fernandez, B., Martin, A., Lachaud, J. R., Jaffe, R. L., Mansour, N. N., Blanquart, G., and Magin, T. E., “Thermodynamic properties of equilibrium carbon-phenolic gas mixtures,” Aerospace Science and Technology, Vol. 66, 2017.
DOI:10.1016/j.ast.2017.02.025
March 2, 2017
Save-the-date! The 9th Ablation Workshop will be held August 30-31, 2017 at Montana State University in beautiful Bozeman, Montana, not far from Yellowstone National Park! The local organizer will be Prof. Tim Minton (Montana State University), and the co-organizer will be Prof. Alexandre Martin (University of Kentucky). E-mail updates in the coming months will provide reminders about abstract submission, registration, and accommodations. As always, you should also keep an eye on the website (http://ablation2017.engineering.uky.edu) for detailed information. Note that the main two-day meeting will NOT be ITAR restricted, but we plan on having an additional morning session on September 1st for ITAR presentations. If you have any questions, please do not hesitate to contact one of us.
February 17, 2017
Two new conference articles from the 55th AIAA Aerospace Sciences Meeting:
[1] Fu, R., Weng, H., Wenk, J. F., and Martin, A., “Development of a coupled elastic solver for ablation problems,” in 55th AIAA Aerospace Sciences Meeting and Exhibit, AIAA Paper 2017-0439, Grapevine, TX, Jan. 2017.
doi: 10.2514/6.2017-0439.
[2] Schulz, J. C., Stern, E. C., Muppidi, S., Palmer, G. E., Schroeder, O., and Martin, A., “Development of a three-dimensional, unstructured material response design tool,” in 55th AIAA Aerospace Sciences Meeting, AIAA Paper 2017-0667, 2017.
doi: 10.2514/6.2017-0667.
September 19, 2016
A new article was recently published in "Learned Publishing".
Key points
• Publishing articles in predatory or low quality open-access journals has been proven to be easy.
• In the presented case study, the editor replaced the entire submitted manuscript with plagiarized texts, without explicitly informing the authors.
• When strongly motivated to publish, editors and publishers may fraudulently change articles to make them more publishable.
• Replacing the entire content of an article cannot be interpreted as a misguided attempt to improve article quality.
• Plagiarism should not be solely blamed on authors when editors may be the culprits.
[1] Martin, A. and Martin, T., “A not-so-harmless experiment in predatory Open-Access publishing,” Learned Publishing, Vol. 29, No. 4, October 2016.
DOI: 10.1002/leap.1060
July 22, 2016
Two new conference papers of GSIL at the 46th AIAA Thermophysics Conference, part of the AIAA Aviation conference:
[1] Fu, R., Weng, H., Wenk, J. F., and Martin, A., “Application of A New Thermal-Mechanical Coupling Solver for Ablation,” 46th AIAA Thermophysics Conference, AIAA Paper 2016-4432, Washington, D.C., 06 2016.
DOI: 10.2514/6.2016-4432
[2] Winter, M., Butler, B. D., Diao, Z., Panerai, F., Martin, A., Bailey, S. C., Danehy, P. M., and Splinter, S., “Characterization of Ablation Product Radiation Signatures of PICA and FiberForm,” 46th AIAA Thermophysics Conference, AIAA Paper 2016-3233, Washington, D.C., 06 2016.
DOI: 10.2514/6.2016-3233
June 7, 2016
A new report on the comparison of the MR code PATO with FIAT has been published:
This report provides a code-to-code comparison between PATO, a recently developed high fidelity material response code, and FIAT, NASA's legacy code for ablation response modeling. The goal is to demonstrates that FIAT and PATO generate the same results when using the same models. Test cases of increasing complexity are used, from both arc-jet testing and flight experiment. When using the exact same physical models, material properties and boundary conditions, the two codes give results that are within 2% of errors. The minor discrepancy is attributed to the inclusion of the gas phase heat capacity (cp) in the energy equation in PATO, and not in FIAT.
Omidy, A. D., Panerai, F., Lachaud, J. R., Mansour, N. N., Cozmuta, I., and Martin, A., “Code-to-Code Comparison, and Material Response Modeling of Stardust and MSL using PATO and FIAT,” Contractor Report NASA/CR-2015-218960, NASA Ames Research Center, Moffett Field, CA, 2015.
HDL: 2060/20160006963
May 30, 2016
A new paper on the permeability of FiberForm has been published in the International Journal of Heat and Mass Transfer:
A series of experiments was performed to obtain permeability data on FiberForm®, a commercial carbon preform used for manufacturing thermal protection systems. A porous sample was placed in a quartz flow-tube heated by an isothermal furnace. The setup was instrumented to measure mass flow through and pressure drop across the sample. The intrinsic permeability and the Klinkenberg correction, which accounts for rarefied effects, were computed from the experimental data. The role of the gas temperature and pressure on the effective permeability is shown, and it is demonstrated that with proper data reduction, the intrinsic permeability is strictly a function of the micro-structure of the material. A function for the effective permeability of FiberForm, dependent on temperature, pressure, pore geometry, and type of gas is proposed. The intrinsic permeability was evaluated at K0=5.57×10-11 m2, with a Klinkenberg parameter of 8c/dp=2.51×105 m−1 and a reference porosity of ϕ†=0.87.
Panerai, F., White, J. D., Cochell, T. J., Schroeder, O. M., Mansour, N. N., Wright, M. J., and Martin, A., “Experimental measurements of the permeability of fibrous carbon at high temperature,” International Journal of Heat and Mass Transfer, Vol. 101, October 2016, pp. 267–273.
DOI: 10.1016/j.ijheatmasstransfer.2016.05.016
May 25, 2016
A new paper has been published (online) in the CEAS Space Journal:
The spallation phenomenon was studied through numerical analysis using a coupled Lagrangian particle tracking code and a hypersonic aerothermodynamics com- putational fluid dynamics solver. The results show that car- bon emission from spalled particles results in a significant modification of the gas composition of the post-shock layer. Results from a test campaign at the NASA Langley HYM- ETS facility are presented. Using an automated image pro- cessing of short exposure images, two-dimensional velocity vectors of the spalled particles were calculated. In a 30-s test at 100 W/cm2 of cold-wall heat flux, more than 722 particles were detected, with an average velocity of 110 m/s.
Martin, A., Bailey, S. C. C., Panerai, F., Davuluri, R. S. C., Vazsonyi, A. R., Zhang, H., Lippay, Z. S., Mansour, N. N., Inman, J. A., Bathel, B. F., Splinter, S. C., and Danehy, P. M., “Numerical and experimental analysis of spallation phenomena,” CEAS Space Journal, Vol. 8, No. 3, September 2016.
DOI: 10.1007/s12567-016-0118-4
March 21, 2016
A new paper is available in the AIAA Journal of Thermophysics and Heat Transfer:
Omidy, A. D., Panerai, F., Lachaud, J. R., Mansour, N. N., and Martin, A., “Effects of water phase change on the material response of low density carbon phenolic ablators,” Journal of Thermophysics and Heat Transfer, 2016.
DOI: 10.2514/1.T4814
January 1, 2016
The radiative heat transfer inside a low-density carbon fiber insulator is analyzed using a three- dimensional direct simulation model. A robust procedure is presented for the numerical calculation of the geometric configuration factor to compute the radiative energy exchange processes among the small discretized surface areas of the fibrous material. The methodology is applied to a polygonal mesh of a fibrous insulator obtained from three-dimensional microscale imaging of the real material. The anisotro- pic values of the radiative conductivity are calculated for that geometry. The results yield both directional and thermal dependence of the radiative conductivity. The combined value of radiative and solid conduc- tivity are compared to experimental data available in the literature, and show excellent agreement.
Nouri, N., Panerai, F., Tagavi, K. A., Mansour, N. N., and Martin, A., “Evaluation of the anisotropic radiative conductivity of a low-density carbon fiber material from realistic microscale imaging,” Interna- tional Journal of Heat and Mass Transfer, Vol. 95, 2016, pp. 535–539.
DOI:10.1016/j.ijheatmasstransfer.2015.12.004
November 30, 2015
September 25, 2015
New paper about carbon oxidation in the journal "Carbon":
Oxidation is one of the main decomposition mechanisms of fibrous carbon/phenolic ablators employed in thermal protection systems for planetary entry capsules. The oxidation process is driven by two competing mechanisms: diffusion of reactants within the porous medium, and reaction rates at the surface of the fibers. These mechanisms are characterized by the Thiele number. Given that the Thiele number varies during an atmospheric entry, we aim to understand the effects of the diffusion/reaction processes on the decomposition of a porous carbon material in various regimes. We use a particle method for simulations of the oxidation process at microscale. The movement of oxygen reactants is simulated using a Brownian motion technique, and heterogeneous first-order reactions at the surface are modeled with a sticking probability law. To enable simulations of the fiber decomposition on actual materials, we use digitized computational grids obtained using X-ray micro-tomographic imaging. We present results for the oxidation of the substrate of the material used on the Mars Science Laboratory capsule that landed the Curiosity rover. We find that the depth of the reaction zone for this material is critically dependent on the Thiele number.
Ferguson, J. C., Panerai, F., Bailey, S. C. C., Lachaud, J. R., Martin, A., and Mansour, N. N., “Modeling the oxidation of low-density carbon fiber material based on micro-tomography,” Carbon, Vol. 96, January 2016, pp. 57–65.
DOI: 10.1016/j.carbon.2015.08.113
May 2, 2015
New paper just published in the AIAA Journal of Thermophysics and Heat Transfer!
[1] Davuluri, R. S. C., Zhang, H., and Martin, A., “Numerical study of spallation phenomenon in an arc-jet environment,” Journal of Thermophysics and Heat Transfer, vol. 29, no. 3, 2015.
doi:10.2514/1.T4586.
April 19, 2015
[1] Martin, A. and Boyd, I. D., “Modeling of heat transfer attenuation by ablative gases during the Stardust re-entry,” Journal of Thermophysics and Heat Transfer, Vol. 29, No. 3, July 2015.
DOI: 10.2514/1.T4202
[2] Weng, H. and Martin, A., “Numerical Investigation of Thermal Response Using Orthotropic Charring Ablative Material,” Journal of Thermophysics and Heat Transfer, Vol. 29, No. 3, July 2015.
DOI: 10.2514/1.T4576
February 11, 2015
Dr. Francesco Panerai, Research Associate in the research group, is being interview for the IXV re-entry demonstrator:
http://uknow.uky.edu/content/uk-postdoctoral-scholar-contributes-europes-experimental-spaceplane
January 12, 2015
Two new papers are available. The first from the AIAA SciTech2015 conference:
Weng, H. and Martin, A., “Numerical Investigation of Geometric Effects of Stardust Return Capsule Heat Shield,” 53rd AIAA Aerospace Sciences Meeting, AIAA Paper 2015-0211, Kissimmee, FL, January 5-9 2015.
DOI: 10.2514/6.2015-0211
The second from the Journal of Thermophysics and Heat Transfer:
Martin, A., Boyd, I. D., Cozmuta, I., and Wright, M. J., “Kinetic rates for gas phase chemistry of phenolic based carbon ablator decomposition in atmospheric air,” Journal of Thermophysics and Heat Transfer, 2015.
DOI: 10.2514/1.T4184
January 9, 2015
A new paper by Nima Nouri and Alexandre Martin has been published in the International Journal of Heat and Mass Transfer:
http://www.sciencedirect.com/science/article/pii/S0017931014011491
December 5, 2014
Congratulation to Justin Cooper who just won the 1st place in the 2014 Oswald Research and Creativity Competition, Physical & Engineering Sciences category for his paper titled: Flux Matching scheme for the Computation of Accurate Boundary Conditions on a Moving Mesh !!!
December 5, 2014
New NASA award to work on the fundamental properties of heat shields:
http://uknow.uky.edu/content/nasa-awards-uk-researcher-500000-early-stag...
October 29, 2014
[1] Martin, A. and Boyd, I. D., “Strongly coupled computation of material response and nonequilibrium flow for hypersonic ablation,” Journal of Spacecraft and Rockets, Vol. 52, No. 1, January 2015.
doi:10.2514/1.A32847
October 17, 2014
[1] Weng, H., Bailey, S. C. C., and Martin, A., “Numerical study of geometrical effects on charring ablative arc-jet samples,” International Journal of Heat and Mass Transfer, Vol. 80, January 2015, pp. 570–596.
doi: 10.1016/j.ijheatmasstransfer.2014.09.040
September 20, 2014
[1] Weng, H. and Martin, A., “Multi-dimensional modeling of pyrolysis gas transport inside charring ablative materials,” Journal of Thermophysics and Heat Transfer, Vol. 28, No. 4, 2014.
doi:10.2514/1.T4434
[2] Alkandry, H., Boyd, I. D., and Martin, A., “Comparison of Models for Mixture Transport Properties for Flow Field Simulations of Ablative Heat-Shields,” Journal of Thermophysics and Heat Transfer, Vol. 28, No. 4, 2014.
doi:10.2514/1.T4233
March 30, 2014
Francesco Panerai, Alexandre Martin, Nagi N. Mansour, Steven A. Sepka, and Jean Lachaud. "Flow-Tube Oxidation Experiments on the Carbon Preform of a Phenolic-Impregnated Carbon Ablator". Journal of Thermophysics and Heat Transfer, Vol. 27, No. 2, 2014.
doi: 10.2514/1.T4265
February 11, 2014
Miller, M. A., Martin, A., and Bailey, S. C. C., “Investigation of the scaling of roughness and blowing effects on turbulent channel flow.” Experiments in Fluids, Vol. 55, No. 1675, 2014.
July 23, 2013
July 18, 2013
February 13, 2013
Gordon Research Conference on Atmospheric Reentry Physics
Fundamentals of Environment-Materials Interactions, Models and Design Approaches to Meet Emerging Space Needs
http://www.grc.org/programs.aspx?year=2013&program=atmosentry
February 9, 2012
The 5th Ablation Workshop will be held right here, in Lexington, KY, from Feb. 28th to March 1st. More information can be found here: ablation2012.engineering.uky.edu
October 24, 2011
Dr. Ioana Cozmuta, from NASA Ames, will be giving a seminar, as part of the William Maxwell Reed seminar series. More info here: Abstract and Bio (PDF)
October 18, 2011
From the NASA NIX server:
Aerodynamic Heating and Deceleration During Entry into Planetary Atmospheres. Dr. Chapman's lecture examines the physics behind spacecraft entry into planetary atmospheres. He explains how scientists determine if a planet has an atmosphere and how scientists can compute deceleration when the atmospheric conditions are unknown. Symbols and equations used for calculations for aerodynamic heating and deceleration are provided. He also explains heat transfer in bodies approaching an atmosphere, deceleration, and the use of ablation in protecting spacecraft from high temperatures during atmospheric entry. [Entire movie available on DVD from CASI as Doc ID 20070030962. Contact help@sti.nasa.gov]
Aerodynamic Heating and Deceleration During Entry into Planetary Atmospheres
August 12, 2011
Link to the AIAA Award news:
http://www.engr.uky.edu/news/2011/07/martin-wins-prestigious-aiaa-award/
